Fix syscall featurization (#12714)

* Fix syscall featurization

* nudge

programs/bpf/rust/sha256/src/lib.rs

@@ -6,14 +6,30 @@ use solana_sdk::{
     info,
 };
 
-#[no_mangle]
-pub extern "C" fn entrypoint(_input: *mut u8) -> u64 {
-    info!("sha256");
-
+fn test_hasher() {
     let vals = &["Gaggablaghblagh!".as_ref(), "flurbos".as_ref()];
     let mut hasher = Hasher::default();
     hasher.hashv(vals);
     assert_eq!(hashv(vals), hasher.result());
+}
+
+#[no_mangle]
+pub extern "C" fn entrypoint(_input: *mut u8) -> u64 {
+    info!("sha256");
+
+    test_hasher();
 
     0
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    // Pull in syscall stubs when building for non-BPF targets
+    solana_sdk::program_stubs!();
+
+    #[test]
+    fn test_sha256() {
+        test_hasher();
+    }
+}